President Vladimir Putin ordered the Russian navy in the Mediterranean to establish contact with its French counterparts and work together "as allies" in a campaign against the Islamic State group in Syria.

The Italian navy on Friday said it had rescued around 2,500 asylum-seekers from 17 boats in the past 24 hours as good weather conditions in the Mediterranean further boost the influx of asylum-seekers trying to reach Europe.

The Australian government apologised unreservedly to Jakarta on Friday after its navy "inadvertently" violated Indonesian waters during border security operations, but vowed to pursue its policies to halt asylum-seeker boats.

North Korea on Tuesday warned the United States of a "horrible disaster" and put its troops on alert over a massive joint naval drill involving a nuclear-powered US aircraft carrier alongside South Korean and Japanese vessels.